1. Technical Field
The present invention relates to a liquid crystal display apparatus. More specifically, the invention relates to a liquid crystal display apparatus which includes a light-detecting unit that senses an environmental light, controls the brightness of an illuminating unit automatically according to the intensity of the environmental light detected by the light-detecting unit, and achieves an easy inspection of optical-sensor characteristics.
2. Related Art
Application of liquid crystal display apparatuses is rapidly spread not only in recent information communication apparatuses, but also in general electric apparatuses. Since a liquid crystal display panel does not emit light by itself, a transmissive liquid crystal display apparatus having a backlight as an illuminating unit combined thereto is used in most cases. However, in the liquid crystal display apparatuses as described above, specifically, in the case of the liquid crystal display apparatuses that are used in compact mobile information terminals represented by mobile phones or the like, reflective liquid crystal display apparatuses which do not require the backlight are used in most cases in order to reduce power consumption. However, since an environmental light is used as the illuminating unit in the reflective liquid crystal display apparatus, visibility is deteriorated in a dark room or the like. Therefore, reflective liquid crystal display apparatuses using a front light as the illuminating unit and transflective liquid crystal display apparatuses which have both transmissivity and reflexivity are being developed.
The transflective liquid crystal display apparatus is able to display an image using a transmissive portion of a pixel area by illuminating the backlight as the illuminating unit in a dark place and display the image using the environmental light by a reflective portion without illuminating the backlight or the like in a bright place. Therefore, in the transflective liquid crystal display apparatus, constant illumination of the illuminating unit such as the backlight is not necessary, and hence an advantage of significant reduction of the power consumption is achieved.
The transmissive liquid crystal display apparatus is characterized in that the image can be recognized clearly even when the brightness of the backlight is reduced in the dark place, while the image cannot be viewed easily unless the brightness of the backlight is increased in the bright place.
As described above, the liquid crystal displays of the liquid crystal display apparatuses have different visibilities depending on the intensity of the environmental light. Therefore, the invention in which a light detector is provided in the liquid crystal display apparatus to detect the brightness of the environmental light thereby, and control the brightness of the illuminating unit on the basis of a result detected by the light detectors is known (see JP-A-2005-203783).
According to the display apparatus disclosed in JP-A-2005-203783, by the provision of optical sensors in the display apparatus, control of the illuminating unit on the basis of outputs from the optical sensors is achieved. In the display apparatus described above, the optical sensors are formed on, for example, a peripheral area on a liquid crystal display panel assembly (array substrate). Lines used for the optical sensors arranged in the peripheral area are laid around in different areas since input/output signals are completely different from lines provided for driving the liquid crystal. However, the lines laid around the different area from the lines for driving the liquid crystal also have a possibility of defective wirings such as a disconnection or a short-circuit with other lines which are present in the vicinity thereof as in the case of the lines for driving the liquid crystal, an inspection is needed in the course of manufacture.
The applicant of the invention proposes a liquid crystal display panel which is disclosed in JP-A-2006-215302 in order to improve the workability of the inspection of the lines in the course of manufacture, that is, an intermediate functional inspection. The liquid crystal display panel in this disclosure is adapted to allow the intermediate functional inspection to be carried out by extending leader lines from various lines connected to an IC chip, for example, from ends of data lines, forming terminals for inspection at ends of the leader lines, and forming the terminals for inspection at a predetermined matrix, thereby bringing inspection probes formed of a pin or conductive rubber into contact with the terminals for inspection. However, in the liquid crystal display panel in which the workability is improved, when the optical sensor provided in the display apparatus disclosed in JP-A-2005-203783 is provided, the various lines for driving the liquid crystal and the lines connected to the optical sensors are laid at different positions, and hence such the intermediate functional inspection for these lines must be carried out in different processes. Therefore, there arises a problem of increase in inspection time and the cost thereof for the intermediate functional inspection.